title: [Genetic evolution analysis of matrix protein 2 gene of avian influenza H5N1 viruses from boundary of Yunnan province].
abstract: OBJECTIVE
  To elucidate the variation in characterizations and genetic evolution of the matrix protein 2 or ion channel protein(M2) genes of avian influenza subtype H5N1 viruses in the boundary region of Yunnan province from 2008 to 2012.
  
  
  METHODS
  A total of swab samples were collected from foreign poultry such as the junction between Yunnan and Vietnam, Laos,myanmar and wild birds in boundary region of Yunnan province from 2008 to 2012 and screened by H5N1 subtype-specific multiplex RT-PCR. The M genes of H5N1 virus from the positive samples were amplified by RT-PCR and cloned into pMD18-T vectors for sequencing. The alignment and phylogenetic analysis of M2 genes were performed with sequences of the known reference strains.
  
  
  RESULTS
  A total of 71 positive samples were found out of 1240 samples and the positive rate was 5.72%. A total of 14 different M2 sequences were obtained from 30 positive samples and were divided into 3 distinct clades or sub-clades(1.2.1, 1.2.2 and 2) by phylogenetic analysis, 5, 7 and 2, respectively. The M2 genes and Hemagglutinin(HA) genes of H5N1 viruses from the boundary region of Yunnan province had showed different relationship of genetic evolution. The substitution or mutation of key amino acids sites had been found among the domains of epitope, adamantane-resistance, and poultry or human original viral strains.
  
  
  CONCLUSIONS
  The M2 genes of H5N1 subtype viruses in boundary region of Yunnan province from 2008 to 2012 showed genetic divergence and the virus of clade 1.2.2 had become dominant epidemic strain in this region.
authors.affiliation: Yunnan Agriculture University, Kunming 650201, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Xiao
authors.forename: Wen-dong
authors.initials: WD
authors.lastname: Zhang
authors.forename: Bo-fang
authors.initials: BF
authors.lastname: Duan
authors.forename: Huan-yun
authors.initials: HY
authors.lastname: Zhao
authors.forename: Qing-liang
authors.initials: QL
authors.lastname: Liu
authors.forename: Ting-song
authors.initials: TS
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Qiu
authors.forename: Zi-liang
authors.initials: ZL
authors.lastname: Feng
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Quan-shui
authors.initials: QS
authors.lastname: Fan
authors.forename: Ying-guo
authors.initials: YG
authors.lastname: Zhang
authors.forename: Fu-qiang
authors.initials: FQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001717:Birds / Q000821:virology; D002645:Chickens / Q000821:virology; D002681:China; D019143:Evolution, Molecular; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification / Q000235:genetics*; D005585:Influenza in Birds / Q000821:virology*; D010802:Phylogeny; D011200:Poultry / Q000821:virology; D014763:Viral Matrix Proteins / Q000235:genetics*; D000086082:Viroporin Proteins
chemical_list: D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins